Rubberized article



Patented Dec. 15, 1931 UNITED STATES PATENT: orFicE HANS 3101mm) nAEnrEL, or WRENTHAM, MASSACHUSETTS, ASSIGNOR r01 moms y 3. Donna, TRUSTEE, ornnwroN, MASSAC USE TS RUBBERIZED ARTICLE NoDraw'lng.

My invent-ion relates to rubberized articles, such as raincoat material, and particularly but not exclusively to colored articles.

Heretofore it has been common practice to 5 produce raincoat material and like. goods by applying one or more layers of suitably prepared and colored rubber compound to a textile-sheet by use of a calendering machine, after which the rubberized sheet is cured.

1 The constituents of the rubber compound for raincoat and like goods made according to prior methods vary widely, but commonly comprise about 35 to 60 percent rubber, about 8 percent zinc oxide, about 3 percent sulphur,

about 1 to 2 percent accelerator, about? to 4 percent color, a small amount of antioxidant, and the remainder filler such as whiting, clay, and the like. A The zinc oxide component of the rubber compound gives tensile strength to the material; also I have found it acts to secure, in respect to the product, certain beneficial results, commonly and somewhat loosely termed that of activating the accelerator,

and, in respect to this action, to secure a satisfactory product must be used in rela tively large amounts. The coloring material, commonly a. lake or toner, for most colors must be used in large amounts to counteract the dulling efl'ect ofthe zinc oxide. In common practice colors may vary in cost from two to. six dollars per pound, and owing to the large amounts employed constitute a considerable part of the total cost of the rubber compound. Owing to the presence of the large amount of zinc oxide in the compound prepared according to prior methods, it is impossible to secure the full efiectof most colors, and many colors it is impossible to use. If the amount of zinc oxide in the compounds is reduced in an attempt to improve the effect of the coloring material, the accelerator will not be effectively activated, which will result in blooming and other 4 discoloration, while the product will be weak ened and tion.,

By the present invention I have found that an economic saving in expensive coloring material may be effected, while at the same time subject to premature decomposiprepared, by milling, consisting of:

Application filed October 23, 1928. Serial No. 814,548.

securing improved color effects and an improved product, by applying the rubber compound in at least two layers tojthe textile sheet or other backing prior to curin the coloring material being confined so ar as possible to the final layer, which is prefera-bly relatively thin, while the activator? for the accelerator in the final layer is confined so far as'possible to the underlying compound. r r

For example, I, have found that, largely considered, only enough zincoxide need be retained in the finallayer to give that layer its desired physical properties, andthat the activatin of the accelerator therein may be eifecte by including in the base layer that zinc oxide whichv is omitted from the final layer. The employment of aminimum of zinc oxide in the final layer materially reduces the necessary amount of color in that layer, while improving the eflect of such color, and renders possible the use of many colors which in the practice of prior methods it has been impossible to use, and owing to the increasedefiectof the color makes-it in most cases possible to'omit the color entirely from the lower layers. The economic, saving in color by the improved method is very large; for. example, I have found in some cases that only about 1 3 the usual percentage ofcolor need be employed in the final layer, even when the color is entirely omitted from the lower layer, andthat in such cases the final layer, even when somewhat transparent, needbe only about 1/ 3. the total thickness of the rubber coating, resulting in the use of only about 1/9 thesjoolor necessary to employ in the practice of priormethods.

As an example of one way of practising the improved process, but without limitation thereto, compound 'for a base layer may be a v Per cent- Pure rubber 40 Zinc oxide; -i 12 Sulphur g "1 Diphenylguanidine (accelerator) Whiting n remainder "A layer of. theabove compound,about 1/32 of an inch thick, maythenbe applied to a? textile sheet by use of a calendering machine, and while the rubber layer is hot and tacky the surface may be wet by use of a doctor roll to apply thereto a film of solution consisting of a metal carbonate such as magnesium, zinc,,silver, or lead carbonate, or other metal carbonate inert with respect to rubber,

dissolved in ammonia water, which solution,

Percent Pure rubber .40 Zinc o xide 4 Sulphur v /2 Dip-henylguanidine -,(accelerator) Blue-toner (color) V 1 Whiting .re ainder After the final layer is applied-the'rubber surf-ace may be coated withpmetal carbonate as abovedescribed. It may then; be varnished and cured',-the curingfor example consisting in subjecting the material to 270 Fahrenheit for three hours.

1 According -to ,--the practice "of theprior method, w iththe same rubber content (about 40 percent) as ingthe-abovee-xample, about 8 percentzinc oxide, would be necessary and Qto 3 percent color; the exact amount ofcolor depending upon-the particular color 'employed." It will thus be observed in the above example of the practice of the improved method that, as compared to prior methods, the relatively thick base layer contains anexcess ofzinc oxide and no color, and that the final, relatively thin layer contains a minimulnof zincoxide; and a-reduced amount of color, resultingamong other things, asherctofore pointed out, in a great saving of color, Further, as the base layer according to, the presentinvention contains an excess of zinc oxide, it is given an increased tensile strength, resulting in a very durable product, and especially when this layerconstitutes most of the thickness of the rubber compound applied to the textile sheet. The final layer however need not be thinner than'the base'layer as I have found that effective results'may beobtained when different relative thicknesses of the two layers exist, as for example when they are of-the same thickness.

:In respect tothe economic saving-from the reduced amount of-color, accordingto the iii) prior; method when 40 percentrubber at twenty cents per pound is employed, sufficient-compound: for covering 100 square yardsoftextile sheet will cost approximately produce a satisfactory product, for the probable reason that gas lack, when used in amountssuflicient to give full effect ofits color, acts to'neutralize the activating eifect ofthezinc oxide, but that by the improved method; owing to the reduced amount of zinc ;oxide-thereinemployed and consequent reduced necessary amount of color, the full color effect of this coloring material maybe obtained and a satisfactory product produced.

.Any: of the various coloring materials common to the art may be employed in the practice of the invention, as for example various color-lakes and color-toners in almost any desired color and shade, The rubber content of the compound may be varied within wide limits, say from 30 to percent of the compound with addition of substances such as antioxidants and the like for imparting specialphysical or chemical properties to the compound, as desired or deemed expedient. The'invention is not limited to the-use of any particular accelerator, and as substitutes for diphenylguanidine I may employ any of the accelerators commonly used by rubber manufacturers, as for example sulpho-carbanilide, phenylamine, urea, thiourea, monophenylthiourea, diphenylthiourea, monophenylguanidine, triphenylguanidine, other amines, ureas, guanidines,and in fact any accelerator with which best results are secured by use .of zinc oxide, and which will notcause undesired discoloration of the coloring material the amount of the particular accelerator employed in each instance being according to its known effectiveness for the purpose and the amount of sulphur employed,

the sulphur content, as will be understood by those skilled in the art, varying with the rubber content. The amount of'zin'c oxide may be varied to suit the desired physical properties of the product, and for usual requirements- 12 parts zinc oxide to 40 parts rubber in the. base layer and 4 parts zinc oxide to l0 parts rubber in the final'layer will give satisfactory results.

If desired, the tackiness of the rubber sur face of the base'layer may be eliminated, prior to applying the final layer, by other methods. as for example by dusting with clay, or by halogenizat'ion, or treatment with organic salt such as zinc stearate; .or the material, after the base layer has been applied, may be handled by winding it in the receiving roll with a superimposed textile layer to prevent adherence of the tacky rubber surface to the textile-backing of the material. I have found,

however, that treatment of the rubber surface of the base layer with metal carbonates, which may be uniformly applied to give effective results in an exceedingly thin lm, results in better adherence of the final layer than with prior methods, permitting the rubber surface to be embossed in an embossing press with practically no loss of material from separation of the two layers. I have also found that halogenization and treatment with organic salts decreases the elasticity of the product, decreases its durability, and when applied to the colored rubber dulls the color and makes necessary the use of additional color to overcome this dulling effect. Rolling the material with an auxiliarytextile sheet to prevent sticking of the rubber surface to the textile backing, which commonly is flannel, can be done only with expenditure of a large amount of labor owing to the necessary, handling, preparing and cleaning of the auxiliary layer, and, as compared to this method, I have found that by use of the 1mproved method Ican reduce the number of Q5 operators for each calendering machine from about 11 to 5 men.

From the foregoing it will be understood that it is commonly necessary to use zinc oxide with an accelerator to secure best results, the action of the zinc oxide, although it is not whollyunderstood, being commonly termed that of activating the accelerator, usually in the sense that the action of the accelerator is aided or increased by the zinc oxide. However, as the authorities differ or are in doubt as to the manner in which zinc oxide acts to secure best results with particular accelerators, in the appended claims to prevent confusion the effect of zinc oxide on the -accelerator is defined as that of securing-beneficial action of the latter, it being understood that by these words, or words of like import, it is intended toinc-lude what is commonly termed activating of the accelerator, where that is the beneficial result necessary with the particular accelerator employed, or the securing of any beneficial action necessary to affect best results in respect to the product as relates to the effect due to the presence of the particular accelerator employed.

It will be understood that the above description of the improved method, product, and materials employed, is given only as an example of the invention, and that wide deviations from these may be made without departing from the spirit of the invention.

Claims:

1. In a method of making cured colored rubber products, the improvement which comprises placing the rubber in superimposed layers, the outer layer containing color, sulphurand accelerator, and the remaining rubber containing sufficient zinc oxide effectively to secure beneficial action of the accelerator in said outer layer during curing of the product. i

2. In a method of making cured colored rubber products, the improvement which comprises placing the rubber in superimposed layers, the outer layer containing color, sulphur and accelerator, and the remaining rubber containing sulphur, accelerator and suflicient zinc oxide effectively to secure beneficial action of the accelerator in all layers during curing of the product.

3. In a method of making cured colored rubber products, the improvement which comprises placing the rubber in superimposed layers, the outer layer containing the color, and all layers containing zinc oxide, sulphur and accelerator, the amount of zinc oxide in said outer layer being insufficient effectively to secure beneficial action of the accelerator therein, but the aggregateamount of zinc oxide present in said layers being sufficientv effectively to securebeneficial action of the accelerator in all layers.

4. In amethod of making cured colored rubber. products, the improvement which comprises placing the rubber in superimposed layers, all of which contain sulphur, zinc oxide andzaceelerator, the outer layer containing color and only sufficient zinc oxide to improve its tensile strength, but the aggregate amount of zinc oxidein said layers being suflicient effectively to secure beneficial action of, the accelerator in all layers.

5. That improvement in the method of producing colored-rubberized material which comprises applying the rubber compound to the backing in two layers, the final layer containing coloring material and bothlayers containing sulphur, zinc oxide, and accelerator, the amount of zincoxide in the final layer being insufficient effectively to secure beneficial action of the accelerator therein, but the aggregate amount of zinc oxideinboth layers being sufficient effectively to secure beneficial action of the accelerator in both layers, and afterward curing the material.

'6. That improvement in the method of producing colored rubberized material which comprises applying two layers of milled rubber compound to a textile sheet by use of a calendering machine, the coloring material being confined to the final layer and both layers containing sulphur, zinc oxide, andaccelerator, the amount of zinc oxide in the final layer being insufficient effectively to secure beneficial action of the accelerator therein, but the aggregate amount of zinc oxide'in both layers beingsuflicient effectively to secure beneficial action of the accelerator in both layers, and afterward curing the material. 1 I I 7. That improvement in the method of producing colored rubberized material which comprises applying to a textile sheet a base layer of rubber compound containing'sulphur, zincox-ide, and accelerator, coating the surface of said base layer with a film of metal carbonate, applying a second layer ofrubber compound containing sulphur, zinc oxide, accelerator,-and coloring material, and afterward curing the material, said second layer containing insufficient zinc oxide effectively to secure beneficial action of the accelerator therein, but both layers in the aggregate containing suflicient zinc oxide effectively to secure beneficial action of the accelerator in both layers.

8. That improvement in the method of producing coloredrubberized material which comprises applying to a textile sheet a plurality of layers of rubber compound containing sulphur, zinc oxide, and accelerator, the final layer containing the coloring material, the amount of zinc oxide in the final layer being insufiicient effectively to secure beneficial action of the accelerator therein, but the aggregate compound containing sufiicient zinc oxide efiectively to secure beneficial action of the accelerator in all layers.

9; The method of producing colored rubberized material which comprises applying to a textile sheeta plurality of layers of rubber compound containing sulphur, zinc oxide, and accelerator, the final layer being relatively thin and containing the color, the amount of zinc oxide in the final layer being insulficient effectively to secure beneficial action of the accelerator therein, but the aggregate compound containing sutficient zinc oxide effectively to secure beneficial action of the accelerator in all layers.

10. The method of producing colored rubberized material which comprises applying to atextile sheeta plurality of layers of rubber compound containing sulphur and accelerator, the final layer containing the color, and the remaining compound containing sulficient' zinc oxide effectively to secure beneficial action. of the accelerator in the final layer.

'11. That improvement in the method of producing vulcanized rubberized textile sheets which comprises applying to the textile sheet two layers of rubber compound, the outer layer of which is colored, and both layers containing sulphur, zinc oxide, and accelerator, the total zinc oxide present being sufiicient effectively to secure beneficial action of the accelerator in both layers, butthe percentage amount thereof in the inner layer being materially greater than that in the outer layer of which is relatively thin'and colored, and both layers containing sulphur,

zinc oxide, and accelerator, the total zinc oxide present being suflicient effectively to securebeneficial action of the accelerator in omitting from the compound of the finishing layer part of the zinc oxide necessary effectively to secure beneficial action of the accelerator therein and incorporating such part into the compound of the base layer;

14. Vulcanized rubberized sheet 'material comprising a textile sheetcoated with a base ofrubber compound containing a relatively large amount of zinc oxide, and a finishing layer of rubber compound containing'coloring material and a relatively small amount.

ofzinc oxide.

Vulcanized rubberized sheet material comprising a textile sheet coated with a relatively thick base of rubber compound containing a relatively large amount of zinc oxide, and a' relatively thin finishing layer of rubber compound containing coloring material and a relatively small amount of'zinc oxide.

16. Vulcanized rubberized sheet material comprising'a textile sheet coated with a base of rubber compound containing a relatively large amount of zinc oxide, and a finishing layer of rubber compound containing coloring material and a relatively small amount of zinc oxide suificient to give it material tensile strength. I

17 Vulcanized rubberized sheet material comprising a textile sheet coated with a relatively thick base of rubber compound containing a relatively large amount of zinc oxide, and a relativelythin finishing layer of rubber compound containing coloring material and a relatively small amount of zinc oxide sufficient to give it material tensile strength.

18. Vulcanized rubber articles comprising a base of rubber compound containing a relatively large amount of zinc oxide, and a finishing layer of rubber compound containing coloring material and a relatively small amount of zinc oxide.

19. Vulcanized rubber articles comprising a relatively thick base of rubber compound containing a relatively large amount of zinc oxide, and a relatively thin finishing layer of rubber compound containing coloring material and a relatively small amount of zinc oxide. i r

V 20. Vulcanized rubber articles comprising a base of rubber compound containing a relatively large amount of zinc oxide, and a finishing layer of rubber compound containing coloring material and a relativelysmall vulcanized rubberized textile amount of zinc oxide sufiicient to give it material tensile strength.

21. Vulcanized rubber articles comprising a relatively thick base of rubber compound 5 containing a relatively large amount of zinc oxide, and a relatively thin finishing layer of rubber compound containing coloring material and a relatively small amount of zinc oxide sufiicient to give it material tensile strength.

In testimony whereof, I have signed my name to this s ecification.

HAN 

